title: Studies of the effects of agents which alter calcium metabolism on acetylcholine turnover in the rat diaphragm preparation.
abstract: 1 We measured the effects of agents, which are thought to alter the Ca2+ concentration in cells, on tissue and released acetylcholine and choline of rat diaphragm using a gas chromatographic mass spectrometric assay for acetylcholine and choline. 2 Lanthanum and ouabain increased the resting output of acetylcholine, while 4-aminopyridine enhanced the evoked output of acetylcholine. 3 Guanidine first increased and then depressed acetylcholine release. 4 Theophylline, dinitrophenol and the ionophore, A-23187, had no measurable effect on acetylcholine release and tetraethylammonium inhibited the release of acetylcholine. 5 Dinitrophenol caused a highly significant increase of the tissue and released choline. 6 None of these agents increased the tissue acetylcholine content. Tetraethylammonium caused a large decline of tissue acetylcholine while ouabain and guanidine caused smaller reductions of acetylcholine in diaphragm. 7 These results are discussed in relation to the hypothesis that intraterminal Ca2+ activity regulates the synthesis of acetylcholine in diaphragm nerve endings.
mesh_terms: D015761:4-Aminopyridine; D000109:Acetylcholine / Q000378:metabolism*; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D003964:Diaphragm / Q000378:metabolism; D004140:Dinitrophenols / Q000494:pharmacology; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology
chemical_list: D000631:Aminopyridines; D002038:Bungarotoxins; D004140:Dinitrophenols; D006146:Guanidines; D013757:Tetraethylammonium Compounds; D000001:Calcimycin; D010042:Ouabain; D007811:Lanthanum; D015761:4-Aminopyridine; D013806:Theophylline; D019791:Guanidine; D000109:Acetylcholine; D002118:Calcium